Amos densmore



(No Model.) I

A. DENSMORE. METIEIOD OFAND MEANS FOR FORMING SCREW THREADS 0N TUBULAR ARTIGLES.

No. 463,444. Patented Nov. 17,1891.

" NITED STATES PATENT AHOS DENSMORE, OF NEXV YORK, N. Y.

SPECIFICATION forming part of Letters Patent No. 463,444, dated November 17, 1891.

Appliation filed June 3,1891- fierial No. 395,005. (No model.)

This invention relates to improvements in the method or process of screw-threading tubularplugs orsimilararticles. Theinvention also consists in improved machinery for carrying out the said process. 7

The improvement in the process consists in steps or operations as will hereinafter more fully appear, and the mechanism for carrying out the process consists in the construction and combination and arrangement of parts, all substantially as will hereinafter more fully appear and be set forth in the claims.

In the accompanying drawings, Figure 1 is a general or perspective view of the machine for exteriorly screw-threading tubular plugs, Fig. 2 being a sectional View of the working portions of 'the machine shown as in their operative relations to the plugs to be exteriorly threaded, all the parts being shown on a very much enlarged scale. Fig. 3 is a plan view of one of the dies employed. Fig. 4. is a central axial section, enlarged,0f one of the blanks as it appears before being threaded, Fig. 5 being a similar view, but showing the blank as it appears after being threaded. Fig. 6 is a view indicating two of the screw-plugs, which are adapted to serve as a support for a pivotal stud of or for an oscillating or rotatable part.

The method of forming a screw-thread in the wall of a tubular metallic plug, bushing, or other similar article which is usually diminutive consists in placing a die having a circular or peripheral wall around next. to the wall of the tubular article and then compressing the latter at the opposite wall thereof,- whereby the stock adjacent to the threaded die is forced into the threaded die depressions.

In the illustration given the screw-thread is formed upon the outer wall of the tubular plugs or bushings, which are indicated by at. These screw-plugs or bushings are advantageously employed as forming the bearing- -or other appropriate implement.

supports for pivot studs or pins, as indicated at b in Fig. 6. The bushings or plugs screw through threaded perforations to receive them in suitable supporting parts of the machine or device in which they are utilized, and have axial openings therethrough terminating in contracted and tapered cavities 0. Each screw-plug is also provided at its one end with a squared or polygonal enlargement d, where by to turn the fitting a by the use of a wrench There is therefore provided a die A, through which the shank f of the tubular plug may be placed with a loose fit. The die and plug a are on the support or anvil h, there being a space between the under or inner face of the die and the table to accommodate the height of the enlargement b, from which the die A is directly supported. 'The shank portion f of the blank tubular plug having a plain outer wall is projected upwardly through the dieopening at, which is screw-threaded, as shown in Fig. 2 and indicated in Fig. 3.

B represents a reciprocating rod or plunger, which is carried upon a suitable reciprooatory carrier i, which latter is movable in vertical ways of the die-press machine, the reciprocating movement being imparted in any usual or appropriate way. plunger-die B is slightly greater than the diameter of the internal opening in the part a to be threaded, and said plunger-die is also formed tapering at its forward end. The tubular screw-plug 0!. having been placed in the die-block A and the die-block having been adj usted' or presented to the play of the plunger-die b, the latter, on moving down into the opening of the said part a, expands the material or forces it toward and into the depressions in the wall of the die which is next to the outer wall of the part being worked upon.

The plunger-die then being receded, the tn bular plug may be withdrawn from the die with which it is engaged by forcing endwise against the plug for the same may, owing to its elasticity or resiliency, be sprung out of engagement with the threaded die.

What I claim as my invention is 1. The improvement in the method of formin g a screw-thread upon the wall of a tubular metallic article, the same consisting in placing a threaded die next to and around the one The diameter of'the circular surface or wall of the tubular article and then compressing the latter at the opposite wall thereof, whereby the stock adjacent the threaded die is forced into the thread-depressions thereof.

2. The improvement in the method of exte riorly threading the Wall of a tubular plug or article, the same consisting in placing a die having a threaded opening therein, so as to surround and lie next to the outer wall of a plug and then internally applying and expanding pressure upon the plug, whereby the stock at the outer wall thereof is forced into the screw-thread depressions of the surrounding die, substantially set forth. 

